Statistics of Electromagnetic Propagation and Localization

********非技术摘要********研究的目标是获得对无序系统中的波的全面理解。由于所有的传输，无论是电子的还是声学的，光学的还是微波的，都是通过波的传播，因此这项研究将有助于统一不同的学科。由于波沿着不同的弯曲路径重叠，波可以局部化并抑制传输。波局域化的影响决定了物质和能量迁移的性质。对输运的统计理解将通过脉冲和稳态微波测量在随机样本的实现集合的输出表面内和表面上的定位来获得。在随机材料堆叠中的光学测量也将进行，以探索当波被层厚度的不均匀性散射时，从一维问题到三维问题的传播转换。参与这项研究的高中生、本科生、研究生和博士后将学会在探索具有挑战性的基本问题时跳出常规思维，这些问题广泛应用于自由空间和蜂窝通信、电子学、光子学和医学成像。********技术摘要********本项目将探索随机材料中电磁传播的基本方面，这将导致对多重散射介质中的电子和声学以及微波和光波的普遍描述。在稳态实验中纠缠在一起的局域化和吸收的影响将在波的时间演化的微波测量中得到解释。单样本实现中的传播统计量与随机集成中的传播统计量之间的联系将使我们能够显示时域中的局部化是由传输与频移的相关引起的。波的空间范围也将在包含随机并置的介电板的单模狭缝波导中测量。场的分布将被分析为准模加倏逝波的总和。相关的光学测量将在随机分层介质中进行，以探索当波被横向非均匀性散射时，从一维到三维的传播转换。高中生，本科生，研究生和博士后将参与通信，电子，光子学和医学成像应用的合作基础研究。

********NON-TECHNICAL ABSTRACT********The goal of the research is to obtain a comprehensive understanding of waves in disordered systems. Since all transport, be it electronic or acoustic, optical or microwave, is via the propagation of waves, this study will help unify diverse disciplines. As a result of the overlap of waves following different convoluted paths, waves can be localized and transport inhibited. The impact of wave localization determines the character of matter and energy migration. A statistical understanding of transport will be obtained by pulsed and steady-state microwave measurements of localization within and on the output surfaces of collections of realizations of random samples. Optical measurements in random stacks of material will also be carried out to explore the transformation of propagation from a one to a three dimensional problem as the wave is scattered by nonuniformity in the layer thickness. High school students, undergraduates, graduate students and a postdoctoral fellow involved in this research will learn to think out-of-the-box in their exploration of challenging fundamental problems with far-ranging applications to free-space and cellular communications, electronics, photonics, and medical imaging.******** TECHNICAL ABSTRACT********This project will explore fundamental aspects of electromagnetic propagation in random materials that will lead to a universal description of electronic and acoustic, as well as microwave and optical waves in multiply-scattering media. The affects of localization and absorption which are intertwined in steady-state experiments will be unscrambled in microwave measurements of the time evolution of the wave. The connection between statistics of propagation in single sample realizations and in a random ensemble will allow us to show the manner in which localization in the time domain arises from correlation of transmission with frequency shift. The spatial extent of the wave will also be measured inside a single-mode slotted waveguide containing randomly juxtaposed dielectric slabs. The field distribution will be analyzed as a sum of quasimodes plus an evanescent wave. Related optical measurements will be carried out in random layered media to explore the transformation of propagation from a one to a three dimensional problem as the wave is scattered by transverse inhomogeneity. High school students, undergraduates, graduate students and a postdoctoral fellow will be involved in collaborative fundamental research with applications to communications, electronics, photonics, and medical imaging.